Is the "'shimmering text' for waiting" thing really that recent? I feel like that is a bit older, but maybe I am wrong. I have more and more difficulty remembering how long things have been around as I get older.
It wasn't shimmering, but the "hey I'm your computer and this is what I'm doing, oh watch, now I'm doing this" paradigm, was popular in loading screens, installers, and the explicitly personal / anthropomorphized language was on the rise for a long time.
Starting with addressing users personally instead of using neutral language like with labels in physical tools.
Also the "drawing attention" part I think mimics chat interfaces, e.g. Windows installer since Win 8.
But still no shimmering text there. Indeed interesting who started to come up with this.
Other similar, earlier trends I found:
iOS Slide-to-Unlock text!
And the shimmering of loading skeletons is also similar, although they're not text.